1. Field of the Invention
The present invention relates in to general to pipeline connectors and, more particularly, to tapping sleeves for use in attaching a branch pipeline in a fluid supply system.
2. Description of Related Art
A known type of tapping sleeve for attaching a branch pipeline takes the form of a split sleeve which is clamped over the main pipeline to be tapped. A pair of shell gaskets or packing rings are provided that seal between the tapping sleeve and the main pipeline. The shell gaskets are on opposite axial sides of a side opening in the split sleeve for the branch pipe and extend completely around the circumference of the main pipeline.
Another known type of tapping sleeve for attaching a branch pipeline also takes the form of a split sleeve which is clamped over the main pipeline to be tapped. A branch gasket is provided that seals between the tapping sleeve and the main pipeline. The branch gasket encircles a side opening in the split sleeve for the branch pipe.
The manufacture and installation of these related art tapping sleeves has been made difficult and correspondingly expensive by the need for packing grooves and/or retaining rings. Additionally, the tapping sleeves may not adequately lock the main pipeline against relatively high axial forces which may be exerted. For example, when repairing or altering an existing fluid supply system the tapping sleeve may be installed on a pressurized pipeline, the tapping sleeve may be installed in conjunction with a stoppling machine that sets a plug on one side of the main pipeline, and the tapping sleeve may be tapping size on size pipelines, that is, pipelines having generally equal inner diameters. When large axial forces are applied, the related art tapping sleeves may require additional axial support, this can be provided, for example, by end clamps or by welding the tapping sleeve to the main pipeline. Where there is a weld hazardous environment or where the tapping sleeve is to be reclaimed, however, the tapping sleeve cannot even be welded to the main pipe. Accordingly there is a need in the art for an improved tapping sleeve.